1. Field of the Invention
The present invention relates in general to an apparatus for truing a grinding wheel by moving a truing tool following a template and more particularly, to such a truing apparatus designed for truing, preferably, an angle grinding wheel which has two grinding surfaces.
2. Discussion of the Prior Art
In a prior art truing apparatus for angle grinding wheels, a traverse slide is movable in a direction which is approximately parallel to the rotational axis of an angle grinding wheel. A follow slide is guided on the traverse slide for sliding movement in a direction perpendicular to the rotational axis of the grinding wheel, and a truing tool provided on the follow slide is movable by a drive device in the same direction as the sliding movement of the follow slide. As the traverse slide is moved, the follow slide is advanced and retracted toward and away from the grinding wheel, following the template, so that the grinding wheel is trued to have the same profile at its grinding surface as the template.
However, the grinding wheel has to be replaced with a new or fresh one when its diameter is reduced beyond a limited size. When the fresh grinding wheel is attached to the grinding machine, it is often the case that a corner or top edge at which first and second grinding surfaces are conjunctive is not precisely aligned with a corresponding top edge of the template in the sliding direction of the follow slide. It is also often the case that the dimension of the fresh grinding wheel does not precisely coincide with that at the first use of the old one. Thus, if an automatic truing operation were performed right after the fresh grinding wheel is attached to the grinding machine, it would necessarily result that a long truing time is taken because a safety margin in truing operation has to be sufficiently secured to avoid damages on the grinding wheel as well as on the truing tool.
To avoid this inconvenience, in the prior art truing apparatus, an operator has to intervene in truing a fresh grinding wheel at the very first time on the grinding machine. That is, in that event, manual adjustments of the truing apparatus are performed to approach the truing tool to the grinding wheel surface and then to traverse the truing tool over the grinding wheel surface. The truing operation under the operator's observation is completed when the truing of a uniform infeed depth over the entire width of the grinding surface is confirmed by listening to the tool-wheel engagement sound.
Moreover, in the case of such an angle grinding wheel, uneven abrasion or wear often occurs at the two grinding surfaces. In a viewpoint of effective use of the grinding wheel, it is desirable that the truing infeed depth against the grinding wheel be sufficient to revive the grinding capability of the wheel but as small as possible. Accordingly, it is also required that a desired infeed depth against the grinding wheel be given precisely.